Atomic Layer Deposition of Al–W–Fluoride on LiCoO₂ Cathodes: Comparison of Particle- and Electrode-Level Coatings

Abstract

Atomic layer deposition (ALD) of the well-known Al 2 O 3 on a LiCoO 2 system is compared with that of a newly developed AlW x F y material. ALD coatings (∼1 nm thick) of both materials are shown to be effective in improving cycle life through mitigation of surface-induced capacity losses. However, the behaviors of Al 2 O 3 and AlW x F y are shown to be significantly different when coated directly on cathode particles versus deposition on a composite electrode composed of active materials, carbons, and binders. Electrochemical impedance spectroscopy, galvanostatic intermittent titration techniques, and four-point measurements suggest that electron transport is more limited in LiCoO 2 particles coated with Al 2 O 3 compared with that in particles coated with AlW x F y . The results show that proper design/choice of coating materials (e.g., AlW x F y ) can improve capacity retention without sacrificing electron transport and suggest new avenues for engineering electrode–electrolyte interfaces to enable high-voltage operation of lithium-ion batteries.

Challenges and Strategies to Advance High‐Energy Nickel‐Rich Layered Lithium Transition Metal Oxide Cathodes for Harsh Operation

“…While direct coating on the electrode does not deposit on the contact points between LiCoO 2 particles and the current collector, which can still maintain the fast electron transport. [140a] Similar results were demonstrated by Park et al in the case of AlW x F y coating on LiCoO 2 powder and electrode during cycling up to 4.5 V. [141] Therefore, more and more efforts have been devoted to performing surface coating on the Ni-rich electrodes directly. Li and co-workers have conducted a ALD solid-state electrolyte-LiTaO 3 coating directly on NCM111 electrode to improve the cycling and rate performance.…”

Recent Progresses and Development of Advanced Atomic Layer Deposition towards High-Performance Li-Ion Batteries

“…Benefitting from its superior capability to conformally coat the electrode surface, the ALD has been served as an alternative, promising candidate to fabricate all-solid-state thin film batteries [ 109 ]. Several papers previously reported have demonstrated the meaningful contribution of the ALD in this domain, especially solid electrolyte film functioning as a protective layer [ 67 , 100 , 110 , 111 , 112 , 113 , 114 ]. In fact, some SSEs prepared by the ALD have been investigated in recent studies, as summarized in Table 1 , such as LiPON [ 94 , 95 ], Li 7 La 3 Zr 2 O 12 [ 96 ], Li x Al y Si z O [ 97 , 98 ], Li x Ta y O z [ 99 ], Li x Al y S [ 100 ] and Li 2 O-SiO 2 [ 101 ].…”

“…As for coating approaches, the ALD, in sharp comparison with the conventional mechanical mixing and sol-gel methods, affords extraordinary homogeneous cladding layer on the surface with precisely regulated down to sub-nanometers levels [ 5 , 164 ]. In this part, we comprehensively summarize the surface engineering via the ALD for cathode materials including layered cathodes, such as LiCoO 2 [ 111 , 112 , 118 , 148 , 149 ], LiNi x Mn y Co z O 2 [ 113 , 114 , 119 , 154 , 155 , 156 , 157 ], and Li-rich x Li 2 MnO 3 ·(1 − x )LiMO 2 (M = Mn, Ni, Co) [ 161 , 162 , 163 ], and spinel cathodes, such as LiMn 2 O 4 [ 150 , 151 , 152 , 153 ] and LiNi 0.5 Mn 1.5 O 4 [ 52 , 158 , 159 , 160 ], as listed in Table 3 . After careful observation in Table 3 , we can discover that the compounds serving as ALD coating layer for cathode materials can be mainly divided into four categories: metal oxides (Al 2 O 3 [ 118 , 119 , 152 , 154 , 155 , 156 , 159 , 161 , 163 , 165 , 166 ], TiO 2 ...…”

Metal Fluorides as Lithium-Ion Battery Materials: An Atomic Layer Deposition Perspective

“…Despite the large amounts of impurities, the deposition of this material onto a highvoltage lithium-ion battery cathode nickel-manganese-cobalt oxide (NMC) led to significant improvements in its rate performance (Figure 16). [144,159]. The material was studied as an artificial SEI layer for LiCoO2 cathodes and was found to improve the cycling properties of the material.…”